I tried with the particles but the game is too slow and try to sprites.use three sources of particles to achieve the desired effect.Although the effect was quite good.Some examples are pretty good up heavy but very complex, as simple as it seems that the particles but with the defect of being slow.I will try with sprites thanks to all greetings

an animated sprite on top of the main game is the way to go. Unless the rain needs to interact with things its the best way to go about it. Even in 3d most games use a weather "overlay" that just follows the camera. In 3d is a pretty cheap cop out to doin it. In 2d its the opposite lol